Techniques have been developed for administering pharmaceuticals through the skin by absorption. Such techniques are accomplished by devices which typically comprise either a pharmaceutical-containing reservoir enclosed by a synthetic membrane through which the pharmaceutical can diffuse at a controlled rate, or a dispersion of a pharmaceutical in a synthetic polymer matrix in which the pharmaceutical can diffuse at a controlled rate. While such delivery devices work for some pharmaceuticals, the rate of release of other pharmaceuticals is not adequate through synthetic polymers. Either the rate of delivery is too slow to provide an effective dosage given the area of the delivery surface, or in some cases, where prolonged delivery of the drug is desired, delivery is too fast so that the device must be replaced within a short period of time. One situation in which it is desirable to have a drug delivered over a prolonged period of time without removal of the delivery device is the case of delivery of drugs at a wound site around a percutaneous medical device.
Moreover, it is desirable, particularly when dealing with delivery of bioactive agents which are natural products, such as growth factors, that the polymeric matrix from which the drug is delivered be tailored for optimal drug delivery rate. It is difficult to do this when the drug to be delivered is a biological macromolecule, such as an enzyme or surface receptor, since specialized binding functionalities with proper charge density, orientation, hydrophobic domains, etc. are not readily synthesized into synthetic polymers to release the biological macromolecule at a desired controlled rate.
It is thus an object of the present invention to provide a polymeric delivery compositions for controlled release of bioactive agents, particularly biological macromolecules, which is formed of a foam composite of a biopolymer and a synthetic polymer.
It is another object of the present invention to provide drug delivery devices, particularly wound dressings, containing such polymeric delivery vehicles for controlled release of antimicrobial and/or wound-healing agents to aid in the wound healing process.
It is another object of the present invention to provide a catheter-securing and drug delivery device which is easily used which contains a pad comprising a biopolymer which serves as a delivery vehicle for controlled release of a bioactive agent to the catheter wound site.
These and other objects of the invention will be apparent from the following description and appended claims, and from practice of the invention.